Suppression of nonradiative recombination process in directly Si-doped InAs/GaAs quantum dots

We carried out direct impurity doping in InAs/GaAs quantum dots (QDs) by selecting the self-assembled growth steps. The photoluminescence (PL) intensity of the Si-doped QDs is enhanced, and thermal quenching of the PL intensity is found to be considerably suppressed, whereas such improvement was not confirmed in Be-doped QDs. The excitation energy dependences of the PL intensity and the time-resolved PL indicate a reduction in the nonradiative recombination probability during the thermalization of carriers generated by high-energy photons. From these results, excess electrons in doped QDs neutralize and, therefore, inactivate the nonradiative recombination centers created by electron traps. (C) 2011 American Institute of Physics. [doi:10.1063/1.3660794]